Vehicles may use an oil delivery system to lubricate and/or cool various components of an internal combustion engine. An oil pump is included to deliver the oil. The sizing of an oil pump is done to meet peak demand and worst case conditions, which often results in the size of the oil pump being larger than is required for normal operation. A larger than required oil pump to meet normal demand also uses extra fuel because a larger oil pump will generate greater losses. It is therefore desirable to size the oil pump as close as possible to the expected normal requirement.
One approach to sizing the oil pump to the expected normal requirement is shown in EP 1586750. Here, an oil accumulator for an oil supply circuit of an engine is provided, which allows for the size of an oil pump to be smaller.
A potential issue noted by the inventors with the above approach is that there is no control of the flow of oil into and out of the accumulator, which may not reduce fuel usage.
One potential approach to at least partially address some of the above issues relates to an engine oil supply system having an engine drive oil pump to provide a supply of oil at pressure to an oil supply circuit and an oil accumulator which is connected to the oil supply circuit by means of an electronically controlled valve. An electronic controller is arranged to receive an input indicative of at least one engine operating condition and to control the operation of the electronically controlled valve based at least partly upon the at least one engine operating condition. A first pressure sensor to sense the pressure of the oil in the oil supply circuit and supply an output indicative of the sensed oil pressure to the electronic controller and a second oil pressure sensor to sense the pressure of the oil in the oil accumulator and supply an output indicative of the sensed pressure to the electronic controller are included. The electronic controller is operable to compare the output from the first pressure sensor with the output from the second pressure sensor and, if the sensed pressure of the oil in the oil accumulator is lower than the sensed pressure of the oil in the oil supply circuit and a predefined engine operating condition indicating that charging of the oil accumulator with oil will incur substantially no fuel usage by the engine is present, operate the electronically controlled valve to connect the oil accumulator to the oil supply circuit so as to charge the oil accumulator with oil at pressure. The electronically controlled valve allows for the oil supply circuit to be connected or disconnected to the oil accumulator and allows for the oil accumulator to be connected to a demand for oil, overall reducing the oil pump size and using substantially no fuel to charge the oil accumulator.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.